Self-acting friction clutch



Apr. 10, 1923.

' 1,451,506 F. GRAF ET AL SELF ACTING FRICT`ION CLUTCH Filed Nov. lO, 1920 vw/ung .Fcb/rm' 'GRAF 44, a ,la/.w uy/..sus/*rfJfo/v 0 Patented Apr. 10, 1923.

D uNiTED .STATES 'PAiigzNTv oi-Fics FREDRIK GRAF, or KRoKsLAfrr, AND'JGHN WALDEMAR svnNssoN, oF MOLNDAI.,

SWEDEN.

SELF-ACTING FRICTIQN CLUTCH.k

Application intay Nqvember io, i920. semi No. 4.23133.

(GRANTED UNDER THE PROVISIONS or 'ma Aer or MARCH 3, i9z`1,41 sur. yL., 13,13.)

lT all lwhom t muy concern:

a citizen of the `Canton of Thurgau of the Confederated Swiss Republic, and resii'ling at Krokslatt, Sweden, and JOHN WTALDE- MAR S\'nNsso.\', a subject of the King o1' Sweden, and residing at Molndal, Sweden, have invented certain new and useful Iniproveiiients in Self-Acting Friction Clutchl es (for which we have filed applications in Sweden, June 2G. 1919, patent application Number 2942/1919; Germany, November 3.

i 1919, Patent Number 345570; Switzerland, November 11. 1919. Patent Number H6011; France, November 2", 1919, Patent Number 506642; Italy, patent application Number 292/2348, filed June 29, 1920; Spain. patent application Number 11882, filed July 19,' 1920; England., ,Patent Number 176047, ap

204p1icationffiled '(ctober 25, 1920; and Belgiuin, patent application Number 233429, filed October 29, 1920), of which the following is a spe tion, reference being niade to the acco' i 'ing drawing.

The pres vention relates to a friction clutch, the characteristic feature of which comprises a. member fixed to the driving shaftand the circumference of which consists of a divided ring' that is loosely surrounded by a casing, rotatably mounted on said member and so formed. that the ring, when expanded, will be brought into contact with the casing, which forms the driven part of the clutch and which then will be rota-ted.

A friction clutch forming an embodiment of this invention is illustrated in the accompanying drawing, wherein'Fig. 1 is :i sectional elevation of the clutch. Fig. 2

40 illustrates the clutch seen in the longitudinal direction of the driving shaft and the parts of the saine in those positions assumed when the driven part is out of engagement. Fig-3 is an elevation of the member fixed I to the driving sha-ft,'and provided with the divided ring seenin the longitudinal direction of the shaft. Fig. 4 is a view of the clutch similar to Fig. 2 but with the parts in those positions assumed when the driven part is engaged.

Referring to the drawing, 1 designates the driving shaft, to which is fixed, for instance by means of a key 2, a collar pref- Be it known that we. 'FRiinniK GRAF,

erably provided with an 'extension 4,"on which loosely rotates the casing 5, surrounding the collar. The casing 5 is kept in place by means of anv adjusting'ring 6, fixed by 'means of a screw 6 to the shaft 1, or iii any other suitable manner, and to the saine is fixed the driven part orithat part to which the.' power from -the shaft 1' is to be transmitted and which 'on the drawing, by way of example, is shown vas a gearwheel 7, fixed by means of a key 8 to the casing. The collar 3 is provided wit-lithat part. by' means of which the coupling is effecteil and which consists of thedivided ring 9.. (Figure the outer diameter of which is somewhat less than the inner diameter kof the casing 5, surrounding the ring. The difference between said two div Vanieters isl of only such an extent, that' the ring 9 normally may freely rotate inside the casing, but when slightly expanded, as

being divided. 'will have its circumference,

brought into more or less secure engagement with the casing depending on' the de-r gree to which it is expanded. 1

The expansion of the divided ringv9 that is required in order that the same may, by

ine-nt, 1'1 of oval or other suitable shape, for' instance as shown in the drawing, and in this enlargement is fitted a pin 12 of corresponding eross sect-ion. so that, when said pin is turned. the ringinust be more or less expanded, depending on how niuch'the pin is turned, as is easilyunderstood: Integral with the pin 12 is a pin 13 which projects into and is rotatably journalled in another casing .14, fixed to the collar 3 by means of screws 15 or any other suitable mea-ns (and thus also securely connected to the driving shaft 1) so that the opening for the pin 13 in said last named casing 14 will be in front of the enlargement 11, Fig. 3, whereby the pin 12 always will be kept in its place in the said enlargement. The means to regulate the turning of the pin 12 and thus the ex pansio-n of the ring 9 vconsists of a weight or 'balance 16, attachedto the pin 13 and fastened to the same by means `of la. clam ing screw 17. The balance,`which suitab y friction.v be coupled tothe casing 5 is efmay have the shape shown on the drawing, is somewhat shorter than the inner. diameter of the casing 14, where it is placed, and is provided with an opening 1S for the shaft 1 lto ena-ble the lsame to move to one side or the other, ot its central posit-ion, shown in Fig. 2.

lt will be understood that the stiffness or inherent resiliency of the free portion ot' the ring 9 is sulicient to hold the weight 1G in the position shown in Fig. 2 until a predetermined speed of the shaft 1 is attained at which the weight will lag behind the other rotating` parts. By this arrangement it will be clear 4that no matt-er what position the pin 13 occupies when the shaft l comes to rest the weight will be inoperative to cause the ring 9 to expand against the casing 5.

The operation ot the clutch is as follows.

also made to rotate. kThe weight of the balance 1G is. however` so adjusted in relation to the flexibility of the ring 9, that the balance practically is kept in its central position, shown in Fig. 2, as long as the speed of the shaft 1 is low. but when the speed ot the shaft increases and it rotates in the direction of the arrow 19, Fig. 4. the balance will, owing to its inertia. gradually be retarded, the pin 12 heilig then in the same degree turned and the ring 9 thus gradually expanded till the balance finally occupies the position shown in Fig. 4, when the collar 3, by the expansion of. the ring 9,

.is securely coupled tothe casnig"5 and thus the ring 9 extends' practically round the entire inner circumference of the casing 5, it being dividedin only one place and having its one end connected with the collar 3 and its other end free, while on the other hand the expansion of the ring is not effected with the aid ot' a weight or weights being actuated by the centrifugal force but with the aid of a single, centrally positioned,

weight. which during the rotation of the coupling by the increased speed changes its position owing to its being then retarded.

ln the case ot' a shaft. rotating in the direction shown onthe drawing it is easil)- understood that the opening 1G in the ring 9 ought to be directed that way, as shown on the drawing, and the opposite way in case the shaftI rotates in the other direction.

Having now described our invention, what we claim as new and desire to sec-ure by Letters Patent is:

The combination with a driving sha-ft, of a clutch member con'iprising a split annulus having a radially disposed portion secured to said shaft. the walls of t-he split portion being provided with parallel channels having a common axis, a pin provided with a double cam operating between the opposite walls of the opening formed by the channels` a driven member surrounding said clutch member` and a pin operating element comprising a flatportion secured at one end to thc pin and projecting to a point beyond the said shaft and receiving the latter through an arcuate opening therein, the free end of said element being provided with a weighted section adapted, to cause the said element to lag behind the clutch inember when the latter rotates at and beyond a. predetermined speed to turn said pin and expand said annulus into engagement with the. driven nieniber.

In witness whereofwe have hereunto set our hands in presence of two witnesses.

FREDRIK GRAF. JOHN VALDEMAR SVENSSO'N. 

